JPS62133069A - Device and method for forming chemical vapor deposited thin film - Google Patents

Abstract

PURPOSE:To prevent a floating foreign material from being stuck on the surface of a wafer by making both the pressure of a reaction chamber and the pressure of an N2 purge chamber same pressure and communicating both chambers in such a case that film forming reaction is finished in the inside of a reaction furnace and the wafer is freshly loaded. CONSTITUTION:In a device for forming a chemical vapor deposited thin film wherein an N2 purge chamber 6 for a wafer load is successively connected to a reaction furnace 1 via a gate valve 7, the film is formed on a wafer 5 by sending a reaction gas and an N2 carrier gas through the introduction pipes 8, 9 to a reaction furnace 1 and regulating the pressure of the inside of the furnace by means of an exhaust system 12. In case of opening the gate valve 7 which successively connects the reaction furnace 1 to the N2 purge chamber 6 after film formation is finished, an exhaust pump P is driven by opening the damper 18 of the exhaust system 12 and the floating foreign materials of the inside of the furnace are discharged to the outside of the furnace and also the pressure of the reaction furnace 1 is made to same pressure as the pressure of the N2 purge chamber 6. Thereby the floating foreign materials are prevented from being stuck on the surface of the wafer which is packaged in the N2 purge chamber 6 and allowed to react thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a CV t) thin film forming apparatus.More specifically, the present invention relates to a CV t) thin film forming apparatus. Cv1 to light the transport system] In a thin film forming apparatus, the pressure in the reactor and purge chamber is set to the same level before loading the wafer into the reactor to prevent foreign matter from adhering to the wafer.C V D The present invention relates to a thin film forming apparatus.

[Prior Art] One of the methods for forming thin films that is generally widely used in the conductor industry is vapor deposition (CVD).
Chemical Vaporl) epos i
CVD is the process of turning a gaseous substance into a solid substance through a chemical reaction and depositing it on a substrate.

The characteristics of CV I) are that various thin films can be obtained at a deposition temperature considerably lower than the melting point of the thin film to be grown, and that the purity of the grown thin films is high. It is widely used as a passivation film on the surface of semiconductors because its electrical characteristics are stable even when exposed to heat.

Thin film formation by CVD is performed, for example, by supplying a reactive gas (for example, 5iHq+02. or S i Hq +PH3+02) to a wafer heated to about 500°C. 1. The reaction gas described above is blown onto a wafer in a reactor (belljar) using N2 gas as a carrier, and the surface of the wafer is coated with 5i02 or phosphorus silicate glass (
PSG) thin film is formed. Furthermore, two-phase film formation of SiO2 and PSG may be performed.

For example, a reactor (Belljar) has been conventionally used to perform such a thin film forming operation by CVD.
The reactor has a conical buffer covered with a conical cover, a ring-shaped wafer mounting table installed around the buffer so as to be rotatable or rotatable; It is constructed by providing a wafer transport system that sequentially supplies wafers, which are workpieces, onto a table and sequentially carries out the wafers. This wafer transfer system has an N2 purge chamber to prevent the wafer from being oxidized by oxygen in the air.

A reaction gas supply pipe and N2 are installed near the top of the conical cover.
A carrier gas feed pipe is connected.

A heater is provided directly on the wafer mounting table with a slight gap therebetween to hold the wafer at a predetermined i'! +
Heat to +1 degree (eg 500°C). The reaction gas (e.g. 5iHq+02 or S i H4+PH3+02) sent from the reaction gas feed pipe is a substance produced by a chemical reaction (e.g. 5i02 or PSG).
A thin film of is deposited on the surface of the wafer.

[This is the problem that the invention seeks to solve.] In the equipment conventionally used to perform thin film forming operations by CVD, the N2 purge chamber installed in the reactor and wafer transport system cannot be opened or closed. Each is separated by a possible gate valve.

However, when loading wafers into the reactor, if the gate valve is opened and the 1F coverage between the reactor and the N2 purge chamber is not balanced, the reactor atmosphere will flow into the N2 purge chamber and the SiO and/or 5i within
l゛2 foreign matter such as 02 flows into the N2 purge chamber and NN
2. It may adhere to the surface of the wafer mounted in the purge chamber 1, which is to be reacted.

Are these five substances attached to the wafer surface? CV I)
This method has the drawback of creating pinholes in the film, significantly lowering the wafer manufacturing yield.

[The purpose of the present invention is to prevent foreign particles floating in the reactor from adhering to the wafers mounted in the N2 purge chamber when loading the wafers into the reactor. C V I) To provide a thin film forming apparatus.

Another objective of the present invention is to prevent floating foreign matter in the reactor from adhering to the wafer mounted in the N2 purge chamber.
An object of the present invention is to provide a C V f) thin film forming method.

[Means for Solving the Problems] As a means for solving the problems, this invention provides the following:
In a C V I) thin film forming apparatus in which the N2 purge chamber for wafer loading is connected to the reactor via a gate valve, after the film forming reaction in the reactor is completed, a new wafer is loaded into the reactor. When the reactor fF force and N
CV1] A thin film forming apparatus is provided, characterized in that a mechanism for making the pressures of two purge chambers the same is provided.

In addition, as another means to solve this problem, the present invention provides a CVD thin film forming apparatus in which a wafer loading N2 purge chamber is connected to a reactor via a gate valve. In the film forming method, after the film forming reaction in the reactor is completed, when loading a new wafer into the reactor, the reactor pressure and the N2 purge chamber pressure are set to the same pressure before opening the gate valve. A CVI thin film forming method characterized by (1) (2) preventing floating foreign matter in the reactor from flowing into the N2 purge chamber by opening the reactor.

[Function] 11; As described in j, according to the CVD thin film forming apparatus and CV l) thin film forming method of the present invention, when loading the wafer from the N2 purge chamber to the reactor, the 11- In order to keep the forces almost the same, SiO in the reactor
and/or 5i02 from entering the N2 purge chamber from the reactor. As a result, l'? ,
11. It is possible to prevent attachment of stray substances and increase the manufacturing yield of wafers.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a conceptual diagram of an embodiment of the CVD thin film forming apparatus of the present invention.

In FIG. 1, a reactor (bell jar) 1 covers a circular XI-shaped buffer T2 with a conical cover 3, and a ring-shaped wafer mounting table 4 can be rotated or rotated around the two-legged buffer 2. It is installed at i'iJ Noh.

A N2 purge chamber 6 is connected to the reactor 1 via a gate valve 7 for sequentially loading wafers 5, which are workpieces, onto L of the evaporator mounting table 4. N2 gas is supplied to the N2 purge chamber to prevent the wafers mounted in the chamber from being oxidized by oxygen in the air. This N2 purge chamber can also be used for unloading the deposited CVD film from the reactor.

]) jI A reactive gas inlet pipe 8 and an N2 carrier inlet pipe 9 are connected to the vicinity of the point (d) of the conical cover 3.

1); A heater 10 is provided directly below the wafer mounting table 4 with a slight gap therebetween, and heats the wafer 5 to a predetermined temperature (for example, 500° C.).

In the thin film forming operation using the above-mentioned apparatus, for example, a wafer carried into a reaction furnace is heated, and (i
) N2 gas is introduced to replace the air in the furnace, (II) reaction gas is introduced to perform a film forming reaction, and (iii) N2 gas is introduced to perform a film forming reaction.
The steps can be performed in the following order: introducing gas to displace the reactant gas, and (iv) removing the wafer from the furnace.

Replacement of the reactor air and reaction gas with N2 gas is carried out by the reactor+Jl gas system 12 provided at the end of the reactor. This reactor exhaust system 12 consists of an exhaust pipe 14 and an exhaust pump 16, and includes υI゛trachea 14 and tJ[gas pump 1
A damper 18 is disposed in the middle of the trachea 6, and a pressure gauge 20 is disposed in the middle of the trachea υ1 at a position closer to the reactor than the damper.

The reactor pressure control system can be realized using the conventional configuration.

For example, when feeding the reaction gas and the N2 carrier gas into the reactor, the pressure inside the reactor is determined by opening and closing the damper 18. The pressure inside the furnace can be changed depending on the CVD film forming conditions. The lower blade inside the furnace can be detected by 11 force 1 juice 20.

The N2 purge chamber is equipped with an N2 purge gas supply system 22 and an N2 purge gas supply system 22.
A purge gas υL gas system 24 is provided.

Furthermore, in addition to the gate valve 7 connected to the reactor, the N2 purge chamber has an IJ that can be opened and closed for loading and unloading wafers.
2B is provided. The N2 purge gas supply system 22 is
2 N2 supplied from a gas source (not shown)
Vibrator 28 for supplying gas and N2 gas flow i
It consists of a N2 gas flow h1 controller 30 for controlling i1. N2 gas υ16 gas system 24 is connected to JJI trachea 32 and t
In addition to the JI gas pump 34, a damper 36 is disposed between the exhaust pipe and the exhaust pump, and historically, the pressure is is installed.

mf is supplied to the N2 purge chamber 6 by the N2 gas flow control device 30.
? A regulated N2 purge gas is supplied.

The N2 gas in the N2 purge chamber passes through the damper 36 and is evacuated to tJ by the exhaust pump 34. The pressure inside the N2 purge chamber can be detected by pressure 1.38.

The exhaust pump 16 of the reactor jJ+gas system 12 and the υ1:gas pump 34 of the exhaust system 24 of the N2 purge chamber 6 can also be used in common.

Normally, while the film forming reaction is being carried out in the reactor, the reactor pressure and the N2 purge chamber pressure do not need to be at the same pressure.
The minimum amount of N2 purge gas necessary to prevent oxidation of the wafer may be supplied to the N2 purge chamber. Therefore, during the film-forming reaction, the reactor pressure is generally higher than the N2 purge chamber pressure. As a result, if the gate valve between the reactor and the N2 purge chamber is suddenly opened after the film-forming reaction path r, the l'? , foreign particles flow into the N2 purge chamber and adhere to the wafer in the N2 purge chamber.

In order to avoid such an inconvenient state, for example, after the film-forming reaction path r, the damper of the reactor exhaust system is opened and the exhaust pump is driven to remove the residual reaction gas in the furnace and the reactor 1.
7. Discharge the foreign matter to the outside of the furnace and lower the pressure inside the furnace. Then, the gate valve is opened only when the pressure reading of the reactor exhaust system 11 becomes equal to or lower than the reading of the pressure gauge of the N2 purge chamber exhaust system. Alternatively, the same pressure control method may be based on the reactor pressure and control the amount of N2 purge gas so that the N2 purge chamber pressure matches the reactor pressure.

In this way, an inconvenient situation in which foreign matter in the reactor flows into the N2 purge chamber and lowers the wafer manufacturing yield is prevented.

[Effects of the Invention (1) As explained above, according to the CV I) thin film forming apparatus and CVD thin film forming method of the present invention, when loading a wafer from the N2 purge chamber to the reactor, there is a gap between the N2 purge chamber and the reactor. Since the pressures are equalized, floating foreign matter such as SiO and/or 5i02 in the reactor is prevented from flowing into the N2 purge chamber from the reactor. As a result, N2
Prevent floating foreign matter from adhering to the wafer surface before loading in the parts chamber 11. It is possible to increase the manufacturing yield of wafers.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a CVD thin film forming apparatus of the present invention. 1... Reactor 2... Banfa 3... Cover
4... Wafer mounting table 5... Wafer 6... N2
Purge chamber 7...Gate valve 8...Reaction gas feed pipe 9...N2 carrier gas feed pipe 10...Heater 12...Reactor υ (paternal line 14 and 32...
Exhaust pipes 16 and 34...υ1. Air pump 18 and 36...Damper 20 and 38...1 force,
? I-22...N2 purge gas supply system 28...N
2 purge gas supply vibe 30...N2fj flow jil
Controller diagram 1

Claims (6)

[Claims] (1) In a CVD thin film forming apparatus in which the wafer loading N_2 purge chamber is connected to the reactor via a gate valve, a new wafer is loaded into the reactor after the film forming reaction in the reactor is completed. Sometimes reactor pressure and N
_2 A CVD thin film forming apparatus characterized by being equipped with a mechanism for making the purge chamber pressures the same. (2) The mechanism is configured by providing an exhaust system in each of the reactor and the N_2 purge chamber, and incorporating a pressure gauge into each of these exhaust systems. The CVD thin film forming apparatus described above. (3) In the method of forming a CVD film on the wafer surface using a CVD thin film forming apparatus in which the N_2 purge chamber for wafer loading is connected to the reactor via a gate valve, the film forming reaction in the reactor is completed. After that, when loading a new wafer into the reactor, the reactor pressure and the N_2 purge chamber pressure are set to the same pressure, and then the gate valve is opened.
A method for forming a CVD thin film, characterized in that flowing into a purge chamber is prevented. (4) C according to claim 3, characterized in that the pressure in the N_2 purge chamber is made approximately equal to the reactor pressure.
VD thin film formation method. (5) The CV according to claim 3, characterized in that the reactor pressure is made approximately equal to the N_2 purge chamber pressure.
D Thin film formation method. (6) Reading of the pressure gauge installed in the reactor exhaust system and N_
Claim 3, characterized in that the readings of pressure gauges disposed in the exhaust systems of the two purge chambers are the same.
5. The CVD thin film forming method according to any one of items 1 to 5.